Written by Lisa Walton on 29th Apr 2026
There's a reason people give up on camping after one cold night. It's not that they had the wrong sleeping bag, it's that nobody told them about the ground.
This guide covers everything that actually keeps you warm on a UK camping trip, in the right order of priority. Because most of the advice out there starts with "wear layers" when it should start with what's underneath you.
Why You Get Cold Camping (It’s Not What You Think)
Most people assume cold air is the problem. It isn't. The ground is your biggest heat thief. Soil and grass conduct heat away from your body roughly 25 times faster than still air. Your sleeping bag compresses flat beneath your body weight, which eliminates its insulation on the underside entirely.
Think of warmth as a system with a clear priority order:
Warmth: the right priority order
The ground steals heat 25x faster than cold air. Your mat is the most important piece of warmth gear you own.
Choose the right season rating for your conditions. Layer a blanket over the top if temperatures drop further than expected.
Clean, dry thermals make a bigger difference than most gear upgrades. Never sleep in the clothes you’ve worn all day.
Wind shelter, avoiding valley floors, and keeping vents open all affect how warm your tent stays overnight.
Get step one wrong and nothing else matters. Get it right and even a modest sleeping bag will keep you comfortable.
Start From the Ground Up
A self-inflating or insulated air mat is the single most important piece of warmth gear you own. More important than your sleeping bag. More important than your thermals.
Sleeping mats are rated by R-value, the higher the number, the better the insulation:
For most UK family camping May–September, R3 or above will do the job. For shoulder-season or highland trips, aim for R4+.
If you're on a tight budget, doubling up works: lay a closed-cell foam mat underneath an inflatable mat. The foam adds insulation and protects the inflatable from punctures. A tent carpet or even a folded blanket under your sleeping area helps too.
We don't sell sleeping mats (it's not in our product range), but we'd rather you spend £30 on a decent mat than £60 upgrading a sleeping bag that's already warm enough.
Your Sleeping Bag and What Goes Over It
Your sleeping bag handles everything above you. If you're not sure what season rating or fill weight you need, our sleeping bag guide breaks down tog ratings, season ratings, EN/ISO temperature ratings and GSM fill weights in detail.
The quick version for UK camping:
- May–September, lowland sites: A 2-3 season bag with 300gsm synthetic fill handles most nights.
- April, October, or exposed sites: Step up to a 3-season bag or add a sleeping bag liner (adds 5-15°C depending on material).
- November onwards: 4-season territory. Don't gamble on it.
Layering over your bag is an underrated move. If your sleeping bag isn't quite warm enough for the conditions, draping an insulated blanket over the top is cheaper and more practical than replacing the bag entirely. The OLPRO Blanko (250gsm microfibre fill, Sherpa fleece lining) adds roughly the equivalent of a 2-3 season sleeping bag's worth of insulation when layered on top. It also works on its own in mild weather, or as a wearable blanket around camp in the evening.
One more thing: fluff your sleeping bag up when you unpack it. Give it 15-20 minutes to loft before you get in. Compressed fill doesn't trap air, and trapped air is what keeps you warm.
What to Wear to Bed
This is where most people go wrong without realising it. The clothes you've worn all day are damp with sweat, condensation, and ambient moisture. Sleeping in them accelerates heat loss through evaporative cooling.
Change into clean, dry base layers before bed. This alone makes more difference than most gear upgrades. Merino wool or synthetic thermals work best, never cotton, which absorbs moisture and stays cold against your skin.
The essentials:
- Dry thermal top and bottoms (your dedicated "sleeping set")
- Warm socks -- wool or thermal, not the ones you hiked in
- A hat or buff -- you lose a significant amount of heat through your head, especially in bags without hoods
- Gloves if it's really cold -- thin liner gloves take the edge off
Team tip — Lisa, OLPRO
Lay tomorrow’s clothes inside your sleeping bag overnight. They’ll be warm when you put them on in the morning instead of cold and damp from the tent air.
Pitch Smart
Where you put your tent matters more than most people think.
Pitching for warmth
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Shelter from wind
Pitch behind hedgerows, walls, or natural windbreaks. Orient the door away from the prevailing wind. Even a light breeze strips heat from a tent fast.
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Avoid valley floors
Cold air sinks and pools in low spots overnight. A pitch slightly uphill can be several degrees warmer.
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Smaller tents are warmer tents
Your body heat warms the air inside. A two-person tent with two people in it gets noticeably warmer than a six-berth with two people rattling around in it.
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Keep your vents open
Closing every vent traps condensation from your breathing inside the tent. That moisture drips onto your sleeping bag and makes you colder. A small amount of ventilation keeps the air drier.
Eat, Drink, Move
Your body generates heat through digestion and activity. Use both to your advantage before bed.
Eat a proper meal in the evening, something with fat and protein, not just carbs. Fats metabolise slowly and produce sustained heat through the night. Think cheese, nuts, stews with meat, oily fish. Keep a flapjack or handful of nuts by your sleeping bag in case you wake up cold, a quick snack kickstarts heat production.
Stay hydrated during the day. Dehydration impairs your body's ability to regulate temperature. But ease off on fluids in the hour before bed, getting up for the toilet at 3am means losing all the warmth you've stored.
Get your blood moving before you get in your bag. Star jumps, squats, a brisk walk around the campsite, anything that raises your core temperature. Getting into a sleeping bag already warm is far more effective than trying to warm up from cold inside it.
Small Things That Make a Big Difference
These are the tips that experienced campers swear by and guides often bury at the bottom:
Small things experienced campers swear by
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Hot water bottle in the foot of your bag
Fill 10 minutes before bed. No dedicated bottle? A Nalgene or metal water bottle wrapped in a sock does the job.
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Hand warmers
Disposable HotHands sachets or rechargeable electric hand warmers tucked into your bag add targeted warmth exactly where you need it.
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Go to the toilet before bed
Every night-time trip out loses 20–30 minutes of warmth you’ve built up in your bag.
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Get your blood moving before you get in
Star jumps, squats, a brisk walk around the campsite. Getting into a bag already warm is far more effective than trying to warm up from cold inside it.
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Don’t breathe inside your bag
Pulling the bag over your face creates moisture that dampens the fill and reduces insulation. Use the drawcord to cinch the hood, leaving your nose and mouth exposed.
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Limit alcohol before bed
A nightcap feels warming but dilates blood vessels near your skin, which increases heat loss. It also disrupts sleep and makes you need the toilet.
Frequently Asked Questions
Gear that actually keeps you warm
EN ISO-tested sleeping bags from £23 • Sherpa fleece Blankos from £35 • All with lifetime warranty and free UK delivery